1. Field of the Invention
The invention relates to the adaptation of common goggles into goggles having ophtalmic lenses. In particular, it is directed to a method of setting an ophtalmic lens having a plane and a curved surface inside the rim of the goggles.
2. Prior Art
Many attempts have been made to provide goggles with the desired ophthalmic corrections.
In U.S. Pat. No. 2,333,198 Riddel proposes to make use of a clip to hold a magnifying lens inside a pair of goggles. Chan in U.S. Pat. No. 3,051,957 has a spectacle supporting device inside a face mask for diving. Such devices are not reliable and do not offer the needed confort for most sporting activities.
Canadian patent 1,004,403 describes an eye protector making use of a molded lens. Molded lenses offer an inadequate quality of vision. A separate lens is also proposed but is snapped in a peripheral groove.
Quality vision lenses are always surfaced by machines and cannot be the result of a molding operation. Curved and flat surfaces of ophtalmic lenses require high precision and must be grounded within very small tolerances which cannot be achieved by molding. Precision of a quarter of a diopter is a minimal tolerance. Corrections such as astigmatism further complicates the production of ophthalmic lenses.
The proposed solution consists in the combination of a surfaced lens to about any types of goggles which provides a vision comparable to ordinary spectacles but which are solidly secured to the goggles, without allowing water or gas infiltration. The installation of such a lens is not obvious.
It is the object of the present invention to install corrective lenses in goggle which provide the required optical and physical performances.
The ophthalmic lenses must be suitably mounted onto most of the goggles without any motion relative to the goggles to maintain the same line of sight without lateral and angular displacement or relative rotation. The interpupillary distances determine with precision the required separation between the optical axis of both lenses.
Considering that most of the goggles have a front protective lamina which is not circular and which is surrounded by a funnel or conical type shielding, the setting of an ophthalmic lens with the required precision is not obvious. The expected results are further complicated by the fact that the front lamina of goggles which are made of molded plastic are not optically flat and cannot be directly glued to the ophthalmic lens.